Sustainable Water Management Solutions for Large Cities (Proceedings of symposium S2 held during the Seventh IAHS Scientific Assembly at Foz do Iguaçu, Brazil, April 2005). IAHS Publ. 293, 2005, 273-279

1 Institute of Limnology of the Russian Academy of Sciences, Sevastyanova Str. 9, 196105 St Petersburg, Russia

Abstract The state of urban water bodies objectively reflects the level of environmental pollution of large cities. The unsatisfactory water quality of most of them affects negatively on biota and people’s health. Given this situation, the development of a scientifically-based management and decision support system for water bodies is one of the main ecological tasks in St Petersburg city (northwest Russia). An important part of such a system is the set of indicators of the ecological state of urban water bodies. Based on the complex of indicators, suggested in this paper, including chemical, biological, sanitary-bacteriological and loading characteristics, an assessment of the state of 11 water bodies in the St Petersburg region has been made. The main reasons why the ecological state of the water bodies located in the urban area deteriorates, and factors inhibiting self-purification of some of them, have been identified. A simplified method of calculating the critical metal load of urban water bodies is suggested.

Key words bioindicators; external, internal and critical load; organic matter; pollution of bottom sediments; state indicators; sanitary-bacteriological indices